// 向右移位
function shiftRight(number, digit) {
    digit = parseInt(digit, 10);
    var value = number.toString().split('e');
    return +(value[0] + 'e' + (value[1] ? +value[1] + digit : digit));
}
// 向左移位
function shiftLeft(number, digit) {
    digit = parseInt(digit, 10);
    var value = number.toString().split('e');
    return +(value[0] + 'e' + (value[1] ? +value[1] - digit : -digit));
}

// copy from https://gist.github.com/tonyc726/00c829a54a40cf80409f
export function digitUppercase(n) {
    var fraction = ['角', '分'];
    var digit = ['零', '壹', '贰', '叁', '肆', '伍', '陆', '柒', '捌', '玖'];
    var unit = [
        ['元', '万', '亿'],
        ['', '拾', '佰', '仟'],
    ];
    var head = n < 0 ? '欠' : '';
    n = Math.abs(n);
    var s = '';
    for (var i = 0; i < fraction.length; i++) {
        s += (digit[Math.floor(shiftRight(n, 1 + i)) % 10] + fraction[i]).replace(
            /零./,
            ''
        );
    }
    s = s || '整';
    n = Math.floor(n);
    for (var i = 0; i < unit[0].length && n > 0; i++) {
        var p = '';
        for (var j = 0; j < unit[1].length && n > 0; j++) {
            p = digit[n % 10] + unit[1][j] + p;
            n = Math.floor(shiftLeft(n, 1));
        }
        s = p.replace(/(零.)*零$/, '').replace(/^$/, '零') + unit[0][i] + s;
    }
    return (
        head +
        s
            .replace(/(零.)*零元/, '元')
            .replace(/(零.)+/g, '零')
            .replace(/^整$/, '零元整')
    );
};

//   console.log(digitUppercase(30.01)); // > 叁拾元壹分